Ohio's Biting Spiders

In Ohio there are two main groups of spiders that pose a potential hazard to
humans; the recluse spiders and the widow spiders. The two species of recluse
spiders found in Ohio (brown recluse - Loxosceles reclusa, Mediterranean
recluse - Loxosceles rufescens) were both likely introduced by humans.
Other common names for these spiders include "brown spiders" or
"violin spiders." In Ohio, these species have been found only in or near
buildings and they may not survive over the winter outside. As the name
"recluse" suggests these are relatively shy spiders. Their thin tangle
webs are found in the area near the retreat, and if disturbed the spider may
rush out and bite. The recluse spiders are mostly a pale or reddish brown color,
darker on the cephalothorax (front part of body) and legs. On very close inspection
there is a violin-like pattern on the top of the cephalothorax. The spiders have
rather long legs, often spread widely and they are adept at running sideways as
well as forward and backward.

Most recluse bites occur when the spider has taken up residence in a stack of
cardboard or an article of clothing laying on the floor. As the person picks up
the item, or puts on the clothing , the spider is crushed and may bite. The bite
of recluse spiders is often not very painful at the time of the bite but the
pain may become quite severe after a few hours. The injury is rarely
life-threatening except when the victim is very young or aged. Of particular
concern are the slow-healing wounds associated with the bites of brown recluse
spiders. The hemotoxic venom of the brown recluse acts rapidly by restricting
circulation in the capillarybeds surrounding the bite and eventually
leads to the death of nearby tissue. Surgery may be required to close the wound
but is often not appropriate.

The black widow, Latrodectus mactans, and the northern widow, Latrodectus
variolus, are both found in Ohio. Records are distributed across most of
Ohio, but there are few records from the northwestern glaciated regions (areas
covered by glaciers in the past). In
Ohio, the black widow is most often associated with old abandoned buildings,
wooden outhouses and barns. The northern widow may also make its tangle webs
under rocks, logs, in cavities under cliff sides, and in shaded areas of woods.
In both of the species, males and females look quite different, the larger
females are shiny and black with a red hour-glass shaped mark under the abdomen,
in the northern widow the middle part of the hour-glass mark is often missing so
that these females appear to have two red marks. Some individuals may also have
red markings along the back. Males are much smaller and lighter in color with a
variety of red or orange marks, often outlined in white, on the abdomen. Bites
are associated with females, males are not known to bite humans. In both species
the bite can be serious. The actual bite may feel like a needle prick but
eventually causes painful muscle spasms and cramps. Complete recovery is likely
for healthy adults.

There are a few other species of spiders which occur in Ohio that may bite.
For most of these species the bite has few lasting effects. These include the
introduced yellow or agrarian sac spiders (Cheiracanthium inclusum and
Cheiracanthium mildei), the bold jumper (Phidippus audax), the parson
spider (Herpyllus ecclesiasticus), Dysdera crocota (no common
name), and the grass spider (Agelenopsis pennsylvanica). There are a few
spiders which occasionally arrive with produce at the grocery store that are
potential bite risks; huntsman (Heteropoda venatoria) and the banana
spiders (members of the genera Phoneutria, Ctenus or Cupiennnius).
The huntsman and banana spiders are relatively large and active spiders that are
potentially dangerous but usually escape from humans without incident. As a
result of modern produce handling procedures, these animals are very rarely
reported in Ohio today.